Safety-lamp



F. T. FORSTER.

SAFETY LAMP.

APPLICATION FILED JUNE 1. 1917.

1,369,644. Patented Feb. 22,1921.

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Inventor: FT ank T Forster;

F. T. FORSTER.

SAFETY LAMP.

. APPLICATION FILE-D JUNE 7, I917. 1,369,644. Patented Feb. 22,192l. Fi .9. IJO.

g M k In ve ntor Frank T Forster",

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llNlTED fi'l'A'lFlEi FATFLMT OFFMIE.

FRANK I. FORESTER, 0F PITTSFIELD, MASSACI-IUSETTfi, ASSIGNOR TO GENERAL ELEGTRTC ODMPANY, A CORPORATION (1F NEW YORK.

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Specification of Letters Patent.

Patented Feb. 22, an.

Application filed .l'une 7, 1911?. Serial No. 173,289.

I '0 all to 7mm it may concern Be it known that l, FRANK. T. Fons'rnn, a citizen of the United States, residing at Fittsfield, in the county of Berkshire, State of Massachusetts, have invented certain new and useful Improvements in Safety-Lamps, of which the following is a specification.

My invention relates to safety lamps or lanterns for use in mines, explosive factories, and generally wherever an exposed. light source would be dangerous, and it comprises various novel features of operation and construction and various novel combinations and a rangements of parts. Among the advantages obtainable in connection with my invention 1 may mention that the apparatus can be made light and compact, rugged and durable, convenient and of good appearance; that it affords thorough protection against ignition of inflammable gas or vapor in case of breakage, and cannot be tampered'with and rendered dangerous by the person using it; and that the manufacturing cost is moderate. It is also convenient for general use as an emergency or trouble lamp, irrespective of dangers such as it is specially intended to guard against.

it have hereinafter illustrated and described in detail several forms of apparatus which are the best embodiments of the invention at present known to me; but while the invention extends even to their specific features and details, yet it is not confined thereto. Various advantages beside those above mentioned will be apparent from my description, and the scope of the invention will be indicated in my claims.

In the accompanying drawings, Figure 1 is a perspective view of the apparatus as a whole.

Fig. 2 is a fragmentary sectional view showing how the current carrying cable is secured to the battery case.

Fig. 3 is a rear view of the lantern.

Fig. 4: shows the battery case opened up and the battery removed therefrom, and also the key for unlocking the case.

Fig. 5 is an enlarged perspective View of the top or cover shown in Fig. at, in a different position.

Fig. 6 is a fragmentary side View of a contact element shown in Fig. 1.

Fig. 7 shows an enlarged section through the lock of either form of cover.

Figs. 8, 9, and 10 are fragmentary elevations of a battery casing slightly different from that shown in F ig. l; and Fig. 11 is an enlarged perspective view of a corresponding cover.

Fig. 12 shows a mid-section through the lantern; and Fig. 13 is a view of the lantern as seen from directly in front.

Fig. ll is an enlarged plan view of one of the lantern parts shown in Figs. 1, 3, 12, and 13.

Fig. 15 is a fragmentary side view of one of the lamp-holding spring contacts shown in Figs. 12 and 13.

F lg; 16 is an elevation showing-lampholding parts within the lantern, slightly different from those shown in Figs. 12, 18, and 15, and also showing, in section, a part to which they are attached; and Fig. 17 is a plan view of the same parts.

The apparatus shown in Fig. 1 comprises a lantern 20 containing an incandescent electrio lamp 21; a battery case 22; and a flexible cable 23 containing the current leads between the lamp and the battery. The cable 23,. which is sheathed with rubber, is secured to the lantern 20 and to the battery case 22 in any approved manner which will relieve the conductors therein of strain due to a pull on the cable. lln the joint shown in Fig. 2, the cable enters the battery case through an internally tapered nipple 2a, and a tapered rubber gasket 25 is wedged tight around it in said nipple by a sleeve or collar-like follower 26 screwed into the inner end of the nipple,--the screw thread being in a conveniently renewable liner 27 itself screwed or otherwise secured in place. The portion of the cable 23 adjacent the battery case 23 is protected from unduly,

sharp flexure by a flexible sheathing shown as comprising a couple of steel wire coil springs 28 and 29 arranged one within the other. The spring 28 ?which may be of wireof about 0.070 diameter) is secured to the nipple 2st by external threaded engagement, its end being bent and inserted in a hole in said nipple (at 80) to prevent it from unscrewing. The spring 29 (which may be of wire of about 0.045 diameter) is similarly secured by internal threaded engagement inside the nipple 24. The spring 29 being longer than the spring 28, the liexibility of the sheathing as a whole is graded into that of the cable 23 itself without change abrupt enough to be harmful; and

further gentleness of gradation of flexibility may be obtained by having the convolutions of the spring 28 in actual contact with one another for a short distance from the nipple 24 and by making the spring 29 the more flexible. The cable 23 is secured to the lantern 20 by a joint 31 quite similar to the joint at 24, and a single coil spring flexible sheathing 32 (of about the same size wire as 29) is provided to protect the cable at this point. The lantern 20 is provided with a double hook 33 of stout steel wire (see Fig. 3) for securing it on the miners cap.

The battery case 22 shown in Figs. 1, 4 and 8 comprises a narrow casing 35 of suitable metal, such as cast aluminum, for containing the storage cell 36 (Fig. 4), which is shown as having a non-spilling air-vent 37 that fits in a lateral pocket of the casing. The lid or cover 39 (to which the cable 23 is attached) may also be of cast aluminum. It has at one end a hook 40 (see Figs. 4 and 5) adapted to engage and pivot in a slot 41 in the corresponding end of the easing 35, and atthe other end it has a lock 42 adapted to engage a T-shaped projection 43 on the casing. This projection 43 has wearing faces, 44, 44 of steel cast into the aluminum. The edge of the cover 39 has a rabbet 45 that allows it tofit snugly over the edge of the casing 35, and its end that contains the lock extends down over the locking projection 43 to a projecting lug 46 that forms, as it were, the base of the T. To the roof of the cover 39 (over an insulating lining 47) is secured an insulating block 48 (see Figs. 2 and 4) on which are mounted the spring contacts 49, 49 that engage the battery terminals 50, 51. The current leads of the cable 23 enter through a hole in the block 48 and are secured to the contacts 49, 49 by binding screws 53, 53. As shown in Figs. 4 and 6, each of the contacts 49, 49 is of resilient sheet metal punched and bent into a triple hook form. The middle member of the hook engages the knob-like center portion of the corresponding battery terminal 50 or 51, while the outer members engage its flat edge portion. The form of the hook members is such that they wipe the battery terminals in making and breaking contact, which insures good, clean contact. Their springiness is such that it requires some pressure to force the cover 39 on tight and snap the lock 42.

The lock 42 (best shown in Figs. 4, 5, and 7) lies in the thickness of the cover end, the inner side of which is formed by a removable, plate 54. (Fig. 7 shows the cover end with the plate 54 removed to expose the lock mechanism.) This lock 42 comprises a pair of levers 55, 55 with beveled catches 56, 56 on corresponding sides of their corresponding ends, the catches being shown as adjacent or facing one. another so as to engage the faces 44, 44 ot' the locking projection 43. These levers 55, 55 have abutting fulcrum portions 57, 57, and a U-shaped leaf spring 58 fits around their ends and engages their opposite sides between their i'ulcrums and their catches, thus urging the catches toward one another into locking position. A. cam 59 lies between the levers, and acts, when turned, to rock them into unlocking position, with the catches 56, 55 apart. pivot projection 61 on the cam piece 59 tits in a hole in the plate 54, and a corresponding projection 62 on the other side of said cain piece fits in a hole in the end wall proper of the cover casting 40. The end 63 ct this latter projection is triangular (see Figs. 4 and 7), and lies in a hole (54 in a boss on said wall. This hole is of such sit .0. as to take a key 65 with av corresponding triangular socket, yet small enough to make it very difiicult to get hold 01 the projection 63 with any other implement.

Figs. 8, 9 and 10 show the upper portion of a battery casing of sheet metal, such as sheet steel with welded seams, and Fig. 11 shows a correspondingly modified cast metal cover 71. In Figs. 8, 9, and 10 the straps 72, 72 (welded on) for the miners belt appear. The casing 70 has a sheet metal hook 73 welded on at one end, and the cover 71 has for engaging it. a steel pin 74 cast into lugs on the cover. The catches 75, 75 of the cover lock engage steel pins 76, 7G riveted and welded into the cover end, and when the cover is on the casing a pair of pins 77, 7'? lie in the notches 78, 78 in the flange at the edge of the lock recess of the cover end (it is through these notches 7 S, 73 that the pins 76, 76 pass when the cover is being put on) and batlle any attempt to reach the catches 75, 75 with a tool. Pro jections 79, 79 on the cover lie inside of andv support the wall of the casing at the corners of the pocket for the battery vent.

The lantern 20 comprises a sheet metal container in the form of a bowl with a shallow cylindrical bottom portion 80 (Figs. 1, 3, and 12). Near the edge of the bowl is a rabbet 81 in which is seated the edge of a howl-like metal reflector 82, which may have a white enamel reflecting surface. n the edge of the reflector 82 is a rubber gasketring 83 of channel-like cross section, and against the gasket 83 is seated a transparent pane 84 of glass or other suitable material. Beyond the rabbet 81 the edge of the container 20 is first flared outward and then turned inward to form a seat 85 for an expanding retaining ring 86 shown as of springy steel wire. In the bottom of the seat 85 (see Fig. 13) are three slots 87, S7 and 88 in which are engaged outwardly eX- tending portions or projections 89, 89 and 90 of the retaining ring 86, shown as consisting of mere bends in the wire (Fig. 14).

ltlt) When seated in the slots 87, 87, the projections 89, 89 present openings outside of the container edge 85, and a wire 91 .is passed through these openings and its ends sealed together with a soft metal seal 92. This prevents undetected opening of the lantern 20 by unauthorized persons.

In the cylindrical bottom portion 80 of the Container 20 is seated and secured a disk- .like insulating base 93 (Fig. 12) of fiber or other suitable material. In depressions in the surface of this base are secured spring contacts 94, 94 which are bent so as to extend forward through openings in the reflector 82. The flexible cable 23 extends forward through a peripheral notch in the disk 93, and its current leads are secured by binding screws 96, 96 to lugs 97, 97 attached to the spring contacts 94, 94 (Fig. 15). The conical ended terminals 98, 98 of the straightfilament incandescent lamp 21 are seated in enlargements 99, 99 of slots in the ends of the spring contacts 94, 94.

The strength of the transparent pane 84 and the proximity of the lamp 21 thereto are such that any blow which might crush or shatter it must certainly break or crack the bulb of the lamp 21, and the strength of the spring contacts 94, 94 is such that once the lamp bulb is injured at all they will crush it together endwise and complete its destruction. The lamp terminals 98, 98 will then fall clear of the contacts 94, 94, and the lamp filament will cease to glow before any in-rushing gaseous mixture can be ignited by it.

In Figs. 16 and 17 the contact springs 104, 104 are shown as of hook shape. The lamp is held between them. with its conical tending longitudinally across them, and an electric lamp having conical contacts at its ends adapted to enter the slots in said con tact springs and adapted to be readily displaced therefrom by a blow upon the lamp.

2. In safety lamp equipment, the combination of a battery case, a battery in said case with terminals at its upper end, a cover adapted. to fit said case having on its inside contacts adapted to engage the battery terminals, a safety lantern mechanically connected to said cover and electrically connected to said contacts, said casin and cover having at one end mutually corresponding pivotal engagement means adapted and free to be engaged by endwise movement of the cover when turned upward from its locking position, and said contacts and terminals being adapted and arranged to wipe one another when the cover is turned upward or downward, a catch on the other end of the cover from the pivotal engagement means, and a lock for engaging said catch inclosed in the corresponding end wall of the cover.

In witness whereof, I have hereunto set my hand this 4th day of June 1917.

FRANK T. FORSTEB. 

